Factors Influencing Outcomes of the Dysplastic Hip in Nonambulatory Children With Cerebral Palsy.

Abstract

Hip dysplasia in the nonambulatory child with spastic cerebral palsy (CP) is a common condition not always effectively treated with conservative measures even when recognized early. Optimal surgical intervention strategies and timing are not clear from previous studies. Contralateral hips with less severe subluxation in these patients also often undergo surgery and little is known of outcomes of these less severe hips. This study aims to clarify treatment factors related to long term success following hip surgery for subluxation in nonambulatory children with CP. A total of 183 nonambulatory subjects with CP and a minimum of 2-year follow-up were included. All subjects underwent varus rotational osteotomy of the femur; other surgical factors considered were addition of pelvic osteotomy (PO), capsulorrhaphy, and soft tissue releases. Additional factors studied were age at index surgery, sex, and unilateral versus bilateral surgery. Severely subluxated (SS) hips, defined as having >50% migration, were studied separately from contralateral nonsevere hips. Surgeries were deemed successful if final follow-up indicated a migration of <25%; patients with any revision surgeries or >25% migration were categorized as failures. A 60% success rate was found in SS hips and a 68% success rate in nonsevere hips. Age at index surgery did not influence success rates in SS hips. In the nonsevere hips, success was associated with index surgery at older age. The addition of a PO was the only concomitant procedure demonstrated to improve outcomes. In SS hips, those with a successful outcome were 2.5 times more likely to have had a PO. The addition of capsulorrhaphy had a negative effect on the entire group, reducing odds of success to 0.8. No other factors were significant. The findings from this multicenter retrospective study suggest that PO be added to varus rotational osteotomies in patients with severe hip subluxation. Surgery should be undertaken for severe dysplasia without concern for age. The addition of capsulorrhaphy does not improve rate of success. Level III-retrospective comparative study.